Pneumatic picking apparatus for a loom

ABSTRACT

The picker stick of a loom is operated by a pneumatic cylinder and piston motor having a pressure chamber communicating with a closed container for air at a predetermined pressure so that the pneumatic piston is biassed. Hydraulic resetting piston means, operated by a liquid in a resetting chamber, hold the pneumatic piston in an initial position. When the resetting chamber in the hydraulic resetting cylinder is relieved by opening a control valve, the pneumatic piston drives the picker stick whereupon the control valve is shifted to another position so that the hydraulic resetting piston resets the pneumatic piston to the initial position.

United States Patent [191 Hofmann et al.

1461 Sept. 25, 1973 PNEUMATIC PICKING APPARATUS FOR A LOOM [73] Assignee: Alta-Laval Bergedorfer Eisenwerke GmbH, Hamburg, Germany [22] Filed: Apr. 25, 1972 [21] Appl. No.: 247,273

Liebowitz 139/144 Bardsley et al. 139/ 144 Primary ExaminerHenry S. Jaudon Attorney-Michael S. Striker [5 7] ABSTRACT The picker stick of a loom is operated by a pneumatic cylinder and piston motor having a pressure chamber communicating with a closed container for air at a predetermined pressure so that the pneumatic piston is biassed. Hydraulic resetting piston means, operated by a liquid in a resetting chamber, hold the pneumatic piston in an initial position. When the resetting chamber in the hydraulic resetting cylinder is relieved by opening a control valve, the pneumatic piston drives the picker stick whereupon the control valve is shifted to another position so that the hydraulic resetting piston resets the pneumatic piston to the initial position.

12 Claims, 3 Drawing Figures PATENTED 3,760,849

SHEET 1 UP 3 PNEUMATIC PICKING APPARATUS FOR A LOOM BACKGROUND OF THE INVENTION Pneumatic picking apparatus for a loom is known in which pneumatically produced impact energy is transferred from a pneumatic cylinder directly, or through suitable connecting elements, to the shuttle. Pneumatic picking apparatus has the advantage that the impact energy of the picking means need not be taken from the drive of the loom, so that the loom runs quietly at high speed, with the wear of the loom parts reduced. Another advantage of pneumatic picking apparatus resides in that the apparatus can be continuously adjusted, but pneumatic picking apparatus according to the prior art has the disadvantage of extremely great noise due to the relief of the pressure of the air after each pick. Since the compression of the air is carried out at low efficiency due to the unavoidable dead spaces and the adiabatic process, the main part of the relieved energy is not used for performing useful work, and consequently the energy requirement is accordingly higher.

SUMMARY OF THE INVENTION It is an object of the invention to provide a pneumatic picking device for a loom which retains the advantages of known pneumatic picking apparatus, but avoids its disadvantages.

Another object of the invention is to provide a pneumatic picking apparatus for the shuttle of a loom which is constructed of simple inexpensive parts, and operates at high efficiency and at a low noise level.

With these objects in view, the present invention relates to a pneumatic picking apparatus which includes at least one pressure gas cylinder in which a piston element, displaceable by pressure gas is mounted, and which is used for providing the impact energy required for the pick. In accordance with the invention, the piston forms in the pressure gas cylinder, a pressure chamber which is always filled with gas at a predetermined pressure, and forms, together with a pressure gas container, a permanently closed space. Hydraulic or mechanic resetting means are provided for returning the pressure piston to its initial position after the pressure gas in the pressure chamber has been partly relieved for producing impact energy.

An embodiment of the invention comprises picking means movable between a position of rest and the picking position for driving a shuttle across a loom, pneumatic drive means including a cylinder element, and a piston element forming in the cylinder element a pressure chamber, the piston element being movable and connected with the picking means for movement therewith, a pressure gas container and conduit means connecting the container with the pressure chamber so that the container, the conduit means, and the pressure chamber form a closed space filled with gas, such as air, at a predetermined pressure for biassing the movable piston to move from an initial position to an operative position for moving the picking means to the picking position whereby the pressure in the pressure chamber is partially relieved, resetting means for returning the movable piston from the operative position to the initial position and for holding the movable piston in the initial position whereby the initial predetermined pressure is again restored in the pressure chamber, and the picking means returned to the position of rest, and control means for operating the resetting means to release the movable piston for movement to the operative position so that the movable piston moves the picking means rapidly to the picking position, whereupon the movable piston returns to the initial position and the picking means are returned to the position of rest, for example by a spring.

In the preferred embodiment of the invention, the pressure chambers of one or several pneumatic cylinder elements directly communicate with a container for pressure air without the intermediary of control means. Since the pressure space formed by the pressure air container, the respective conduits, and the pressure chambers form a closed space, and since the pressure air is only partially relieved by each impact of the picking means, the amount of pressure gas, such as air, in the pressure container is substantially unchanged so that only small leakage losses have to be replaced. The pressure in the pressure chamber of the pneumatic cylinder and/or in the pressure gas container, may be adjusted by a constant limit valve to a predetermined pressure in accordance with the requirements of the operational condition.

In one embodiment of the invention, the resetting means for each pressure gas cylinder, include a resetting cylinder with a resetting piston, operated by a liquid, and being connected with an associated pressure gas piston for movement together. Connecting conduits including control valves connect the resetting cylinder with a pump or with a discharge reservoir, depending on the desired operation of the pneumatic cylinder and piston elements. By suitable operation of the control valves, the resetting cylinder is alternately connected with a pressure source, such as a hydraulic pump, or with the low pressure reservoir.

According to one modification, the pressure gas piston and the resetting piston are connected by a common piston rod, while in another modification, the pressure gas cylinder and the resetting cylinder are combined in a single cylinder containing a movable piston which forms in the cylinder on one side a pressure chamber for pressure gas and on the other side a resetting chamber for the operating liquid. In such an arrangement, it is preferred to construct the common piston as a stepped piston.

For safety reasons, it is advantageous to use a gas,.for example nitrogen, which is not inflammable, in order to prevent oxidation of the operating liquid leaking along the inner surface of the cylinder into the chamber filled with pressure gas.

In order to obtain a rapid succession of picks, it is advantageous to position the control valve closely spaced from the liquid filled bydraulic resetting cylinder and to provide flow cross-section as large as possible so that a picking operation started by operation of a control valve, is not braked by the operating liquid which has to be pushed out of the resetting cylinder by the pressure gas operated piston. Between the pump and the control valves, a pressure container for the operating liquid is advantageously provided. I

The piston rod of the pressure gas piston carries a pulley which is connected by a strap to the picking lever and to a holding lever which is locked during the picking operation, but released by the locking means during the return of the picking means to the position of rest by means of a spring. When the pressure gas piston is reset, at the same time the holding lever is locked.

Under some operational conditions, it is advisable to replace the hydraulic resetting means by mechanical resetting means, driven by a separate motor so that the force required for resetting the picking means is not taken from the motor driving the loom.

The control valves and the locking means for the holding lever are operated by known, preferably electric, control means depending on the position of movable parts of the loom, particularly the crankshaft and- /or the flaps of the shuttle boxes.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic front view illustrating a loom provided with the pneumatic picking apparatus according to one embodiment of the invention;

FIG. 2 is a schematic diagrammatic view illustrating the pneumatic drive means of the picking means, the hydraulic resetting means, and control means including control valves for operating the resetting means; and

FIG. 3 is a fragmentary front view illustrating a mechanism for returning the picking means to a position of rest after a pick.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The pneumatic picking apparatus illustrated in FIGS. 1 and 2 has pneumatic drive means including pneumatic cylinders 3 and 4 arranged between the walls 1 and 2 of the loom, and connected by connecting conduits 5 and 6 without any control devices, directly with a pressure gas container 7. In each pneumatic cylinder 3 and 4 is guided a pneumatic piston 8 and 9, respectively, which are secured to a piston rod 10 and 11, respectively. At the end of each piston rod 10 and 11 there is mounted a pulley l2 and 13 over which is guided a strap 14 and 15 secured to the loom walls 1 and 2, respectively, at one end, and being secured to the lower end of the picking lever 16 or 17 at the other end. The picking levers l6 and 17 carry at the upper ends pickers l8 and 19 by which a shuttle is driven across the loom when the picking means 16,18 and 17,19 are moved from a position of rest to a picking position in an angular movement. The lower ends of the picking levers 16 and 17 are pivotally mounted on stationary supports. Springs 20 and 21 return the picking means to the initial position of rest after a pick.

The pneumatic pistons 8 and 9 are returned to the initial positions thereof by associated hydraulic resetting cylinders 22 and 23 in which hydraulic resetting pistons 24 and 25 are mounted respectively, the hydraulic resetting pistons being connected by piston rods 26 and 27 with the piston rods 10 and 11 of the pneumatic pistons 8 and 9 for movement together.

As shown in FIG. 2, the pneumatic cylinders 3 and 4 are connected by conduits 5 and 6, which do not con tain any valves, with a pressure gas container 7 which is connected with a source of pressure gas 29 by a supply conduit 28 in which a constant pressure limit valve 30 is provided. The gas in pressure container 7 can be discharged by opening a valve 32.

The hydraulic resetting cylinders 22 and 23 are connected by conduits 45 and 46 and shiftable control valves 41 and 42 with discharge conduits 47 and 48 or with connecting conduits 39 and 40 with the pressure outlet of a pump 35 which is driven by motor 36, and which sucks the operating liquid through a suction conduit 34 out of the open reservoir 33, and presses the operating liquid through a check valve 38 and a storing conduit 43 into a closed pressure container 44 for the operating liquid. The check valve 38 prevents a flowing of the operating liquid into the outlet conduit 37 of the pump 35. Control valves 41 and 42 are operated by suitable devices, not shown, and including electromagnetic operating means for the valves 41, 42 which are actuated depending on the position of movable parts of the loom, for example the cam shaft or the flaps of the shuttle boxes, not shown.

Due to the provision of a source of pressure gas 29, and of the pressure limit valve 30, a pressure of, for example, 6 atmospheres is maintained in the pressure chambers 30 and 4a of the pneumatic cylinders 3 and 4, and in the pressure gas container 7, the pressure being, for example, 6 atm. The pump 35 maintains in the pressure liquid container 44 and in conduits 39 and 40 a far higher pressure of, for example, atm. In the condition illustrated in FIG. 2, the hydraulic resetting cylinders 22 and 23 are connected by control valves 41 and 42 with the conduits 39 and 40 so that in the resetting chambers of the hydraulic resetting cylinders 22 and 23, a pressure of about 120 atm. prevails. If, for example, a pick from the left to the right as viewed in FIG. 1 is to take place, control valve 41 is shifted, for example under the control of the flaps of the shuttle boxes and of the cams on a cam shaft of the loom, so that the hydraulic resetting cylinder 22 is connected by conduit 45 with the discharge conduit 47 so that the pressure in the hydraulic resetting cylinder 22 rapidly drops, permitting the gas under pressure in the pressure chamber 3a of the respective pneumatic cylinder 3, to push the pneumatic piston 8 rapidly to the right, as viewed in the drawing, so that the picking lever or picking stick 16 is pulled to the right by the strap 14 and picks the shuttle in an open warp shed across the loom from the left to the right as viewed in the drawing. After a pick, control valve 41 is immediately returned to the control position illustrated in FIG. 2, and the hydraulic resetting piston 24 in the hydraulic resetting cylinder 22 is shifted to the left by the operating liquid flowing out of the pressure container 44 against the substantially lower gas pressure in the pneumatic cylinder 3 so that, together with the hydraulic resetting piston 22, the pneumatic piston 8 is shifted in the pneumatic cylinder 3 by the piston rod 26 to the left for resetting the pneumatic piston 8, while the gas in the pressure chamber 3a is again highly compressed and the pneumatic piston 8 assumes again its initial position so that the apparatus is ready for the next pick. By suitable operation of the control valve 42, a picking operation is carried out across the loom from the right to the left as viewed in FIG. 1.

While in the embodiment of FIG. 1, the strap 14 has one end secured to the picker stick l6 and another end secured to a fixed portion of the loom frame, the modified embodiment shown in FIG. 3 has a strap 14 or 15,

one end of which is secured by screw 51 to a holder lever 50 whose lower end is mounted for pivotal movement on a fixed support. A locking latch 52 pivoted about a pin 53 and biassed by spring 56, tends to engage a recess at the free end of holding lever 50 to lock holding lever 50 so that, when the pulley 12 is retracted by the pneumatic piston 8, the picking means 16,18 are rapidly moved in a picking operation. After the pick, an electromagnet 55 is energized to release the locking latch 52 so that spring 20 can turn the picking stick 16 to the illustrated initial position. During the return of the pneumatic piston 8 by the resetting piston 24 and piston rod 26, the bracket 57 on piston rod 10 is displaced together with a rod 58 guided in a stationary bearing 29 so that rod 58 returns the holding lever 50 in counterclockwise direction to the illustrated position in which the locking latch 52 again locks holding member 70 to provide a fixed attaching point for one end of strap 14 or 15.

A preferred embodiment of the picking apparatus has been illustrated and described, but it will be understood that various modifications are possible. For example, the pneumatic cylinder can be mounted on the sley, and directly act on the picking stick without any intermediate connection. Furthermore, the positions of the pneumatic cylinder and of the hydraulic resetting cylinders may be exchanged, so that the connecting piston rods 26, 27 are subjected to tensile stresses. The mechanism illustrated in FIG. 3 is then accordingly modified.

The pneumatic picking apparatus of the invention can be used for driving and accelerating shuttles of all kinds, including gripper shuttles which do not carry bobbins. The arrangement and the dimensioning of the pneumatic cylinder and of the hydraulic resetting cylinder can be selected depending on the construction of the loom and on the types of pressure gas and operating liquid which are being used,

In certain cases, water can be used as operating liquid pumped by pump 35. The apparatus of the invention is particularly suited for looms of great transverse width particularly for looms having more than two sley motions. Since many modern loops are already provided with hydraulic devices, the pneumatic picking apparatus of the invention can be built into existent looms without great difficulties.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of picking apparatus for looms differeing from the types described above.

While the invention has been illustrated and described as embodied in a pneumatic picking apparatus for a loom including pneumatic drive means including a pneumatic cylinder forming with a pressure gas container a closed space in which a predetermined pressure prevails, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

We claim:

1. Pneumatic picking apparatus for a loom, comprising, in combination, picking means movable between a position of rest and a picking position for driving a shuttle across the loom; pneumatic drive means including a cylinder element, and a piston element forming in said cylinder element a pressure chamber, one of said elements being movable and connected with said picking means for movement therewith; a pressure gas container and conduit means connecting said container with said pressure chamber so that said container, said conduit means, and said pressure chamber form a closed space filled with gas at -a predetermined pressure for biassing said movable element to move from an initial position to an operative position for moving said picking means to said picking position whereby the pressure in said pressure chamber is partially relieved; resetting means for returning said movable element from said operative position to said initial position and for holding said movable element in said initial position whereby the initial predetermined pressure is again restored in said pressure chamber, and said picking means returned to said position of rest, said resetting means including a resetting cylinder element and aresetting piston element forming in said resetting cylinder element a resetting chamber, one of said resetting elements being movable and connected with said movable element for movement; and control means for operating said resetting means to release said movable element for movement to said operative position so that said movable element moves said picking means rapidly to said picking position, and to thereafter return said movable element to said initial position and said picking means to said position of rest, said control means including a source of operating fluid, a discharge area, and control valve means having a first control position for connecting said resetting chamber with said source so that said movable resetting element moves said movable element to said initial position and said picking means to said position of rest,-and a second control position for connecting said resetting chamber with said discharge area so that said predetermined pressure in said pressure chamber moves said movable element to said operative position and said picking means to said picking position.

2. Picking apparatus as claimed in claim 1 wherein said conduit means have an open flow cross-section between said pressure chamber and said container to permit unobstructed flow.

3. Picking apparatus as claimed in claim 1 further comprising gas supply means including a supply conduit for supplying gas at a predetermined pressure to said container and said conduit means so that said pressure chamber is filled with gas at said predetermined pressure; and constant limit valve means in said supply conduit for maintaining said predetermined pressure in said closed space.

4. Picking apparatus as claimed in claim 1 wherein said one movable element is said piston element; and wherein said movable resetting element includes a resetting piston and a piston rod rigidly connecting said resetting piston with said piston element.

5. Picking apparatus as claimed in claim 1 wherein said control valve means is located adjacent said resetting cylinder element communicating with said resetting chamber, and has a large flow cross section to permit rapid discharge from said resetting chamber into said discharge area.

6. Picking apparatus as claimed in claim 1 wherein said source of operating fluid includes a pump for an operating liquid, a pressure container, and a pressure conduit connecting said pump with said pressure container, said pressure conduit communicating with an inlet of said control valve means.

7. Picking apparatus as claimed in claim 1 wherein said picking means include a picking lever having a pivotally mounted lower end for angular movement between said position of rest and said picking position, and an upper end for driving the shuttle, a pulley mounted on said movable element, and a strap having one end secured to said picking lever, and the other end fixed, said strap passing about said pulley so that movement of said movable element with said pulley to said operative position causes movement of said picking lever to said picking position, and spring means connected with said picking lever and biassing said picking lever toward said position of rest.

8. Picking apparatus as claimed in claim 7 wherein said picking means further include a holding lever mounted for angular movement and being fixedly secured to said other end of said strap, and locking means for locking said holding lever when said movable element moves to said operative position and transmits force through said strap to said picking lever; and wherein said control means include means for unlocking said holding lever while said spring means moves said picking lever to said position of rest; and wherein said movable-element includes means for returning during movement to said initial position, said holding lever to a position in which it is locked by said locking means.

9. Picking apparatus as claimed in claim 8 wherein said control means include operating means controlling said resetting means, and being actuated by movable parts of the loom.

l0. Pneumatic picking apparatus for a loom, comprising, in combination, picking means movable between a position of rest and a picking position for driving a shuttle across the loom; pneumatic drive means including a cylinder element, and a piston element forming in said cylinder element a pressure chamber, said piston element being movable and connected with said picking means for movement therewith, said piston element forming in said cylinder element at one end a pressure chamber and at the other end a resetting chamber; a pressure gas container and conduit means connecting said container with said pressure chamber so that said container, said conduit means, and said pressure chamber form a closed space filled with a gas at a predetermined pressure for biassing said movable element to move from an initial position to an operative position for moving said picking means to said picking position whereby the pressure in said pressure chamber is partially relieved; resetting means comprising said resetting chamber for returning said movable piston element from said operative position to said initial posi tion and for holding said movable piston element in said initial position whereby the initial predetermined pressure is again restored in said pressure chamber, and said picking means returned to said position of rest; and control means for operating said resetting means to release said movable piston element for movement to said operative position so that said movable piston element moves said picking means rapidly to said picking position, and to thereafter return said movable piston element to said initial position and said picking means to said position of rest, said control means including a source of an operating fluid, a discharge area, and control valve means having a first control position for connecting said resetting chamber with said source so that said movable piston moves to said initial position and moves said picking means to said position of rest, and a second control position for connecting said resetting chamber with said discharge area so that said predetermined pressure in said pressure chamber moves said piston element to said operative position and said picking means to said picking position.

1 l. Picking apparatus as claimed in claim 10 wherein said piston element is stepped so that the effective areas of said pressure chamber and said resetting chambers are different.

12. Pneumatic picking apparatus for a loom, comprising, in combination, picking means movable between a position of rest and a picking position for driving a shuttle across the loom; pneumatic drive means including a cylinder element, and a piston element forming in said cylinder element a pressure chamber, one of said elements being movable and connected with said picking means for movement therewith; a pressure gas container and conduit means connecting said container with said pressure chamber so that said container, said conduit means, and said pressure chamber form a closed space filled with gas at a prcdetermined pressure for biassing said movable element to move from an initial position to an operative position for moving said picking means to said picking position whereby the pressure in said pressure chamber is partially relieved; resetting means for returning said movable element from said operative position to said initial position and for holding said movable element in said initial position whereby the initial predetermined pressure is again restored in said pressure chamber, and said picking means returned to said position of rest, said resetting means including resetting piston and cylinder means; and control means for operating said resetting means to release said movable element for movement to said operative position so that said movable element moves said picking means rapidly to said picking position, and to thereafter return said movable element to said initial position and said picking means to said position of rest, said control means including control valve means controlling said resetting piston and cylinder means to reset and release said pneumatic drive means, and operating means for said control valve means actuated by movable parts of the loom. 

1. Pneumatic picking apparatus for a loom, comprising, in combination, picking means movable between a position of rest and a picking position for driving a shuttle across the loom; pneumatic drive means including a cylinder element, and a piston element forming in said cylinder element a pressure chamber, one of said elements being movable and connected with said picking means for movement therewith; a pressure gas container and conduit means connecting said container with said pressure chamber so that said container, said conduit means, and said pressure chamber form a closed space filled with gas at a predetermined pressure for biassing said movable element to move from an initial position to an operative position for moving said picking means to said picking position whereby the pressure in said pressure chamber is partially relieved; resetting means for returning said movable element from said operative position to said initial position and for holding said movable element in said initial position whereby the initial predetermined pressure is again restored in said pressure chamber, and said picking means returned to said position of rest, said resetting means including a resetting cylinder element and a resetting piston element forming in said resetting cylinder element a resetting chamber, one of said resetting elements being movable and connected with said movable element for movement; and control means for operating said resetting means to release said movable element for movement to said operative position so that said movable element Moves said picking means rapidly to said picking position, and to thereafter return said movable element to said initial position and said picking means to said position of rest, said control means including a source of operating fluid, a discharge area, and control valve means having a first control position for connecting said resetting chamber with said source so that said movable resetting element moves said movable element to said initial position and said picking means to said position of rest, and a second control position for connecting said resetting chamber with said discharge area so that said predetermined pressure in said pressure chamber moves said movable element to said operative position and said picking means to said picking position.
 2. Picking apparatus as claimed in claim 1 wherein said conduit means have an open flow cross-section between said pressure chamber and said container to permit unobstructed flow.
 3. Picking apparatus as claimed in claim 1 further comprising gas supply means including a supply conduit for supplying gas at a predetermined pressure to said container and said conduit means so that said pressure chamber is filled with gas at said predetermined pressure; and constant limit valve means in said supply conduit for maintaining said predetermined pressure in said closed space.
 4. Picking apparatus as claimed in claim 1 wherein said one movable element is said piston element; and wherein said movable resetting element includes a resetting piston and a piston rod rigidly connecting said resetting piston with said piston element.
 5. Picking apparatus as claimed in claim 1 wherein said control valve means is located adjacent said resetting cylinder element communicating with said resetting chamber, and has a large flow cross section to permit rapid discharge from said resetting chamber into said discharge area.
 6. Picking apparatus as claimed in claim 1 wherein said source of operating fluid includes a pump for an operating liquid, a pressure container, and a pressure conduit connecting said pump with said pressure container, said pressure conduit communicating with an inlet of said control valve means.
 7. Picking apparatus as claimed in claim 1 wherein said picking means include a picking lever having a pivotally mounted lower end for angular movement between said position of rest and said picking position, and an upper end for driving the shuttle, a pulley mounted on said movable element, and a strap having one end secured to said picking lever, and the other end fixed, said strap passing about said pulley so that movement of said movable element with said pulley to said operative position causes movement of said picking lever to said picking position, and spring means connected with said picking lever and biassing said picking lever toward said position of rest.
 8. Picking apparatus as claimed in claim 7 wherein said picking means further include a holding lever mounted for angular movement and being fixedly secured to said other end of said strap, and locking means for locking said holding lever when said movable element moves to said operative position and transmits force through said strap to said picking lever; and wherein said control means include means for unlocking said holding lever while said spring means moves said picking lever to said position of rest; and wherein said movable element includes means for returning during movement to said initial position, said holding lever to a position in which it is locked by said locking means.
 9. Picking apparatus as claimed in claim 8 wherein said control means include operating means controlling said resetting means, and being actuated by movable parts of the loom.
 10. Pneumatic picking apparatus for a loom, comprising, in combination, picking means movable between a position of rest and a picking position for driving a shuttle across the loom; pneumatic drive means including a cylinder element, and a piston element forming In said cylinder element a pressure chamber, said piston element being movable and connected with said picking means for movement therewith, said piston element forming in said cylinder element at one end a pressure chamber and at the other end a resetting chamber; a pressure gas container and conduit means connecting said container with said pressure chamber so that said container, said conduit means, and said pressure chamber form a closed space filled with a gas at a predetermined pressure for biassing said movable element to move from an initial position to an operative position for moving said picking means to said picking position whereby the pressure in said pressure chamber is partially relieved; resetting means comprising said resetting chamber for returning said movable piston element from said operative position to said initial position and for holding said movable piston element in said initial position whereby the initial predetermined pressure is again restored in said pressure chamber, and said picking means returned to said position of rest; and control means for operating said resetting means to release said movable piston element for movement to said operative position so that said movable piston element moves said picking means rapidly to said picking position, and to thereafter return said movable piston element to said initial position and said picking means to said position of rest, said control means including a source of an operating fluid, a discharge area, and control valve means having a first control position for connecting said resetting chamber with said source so that said movable piston moves to said initial position and moves said picking means to said position of rest, and a second control position for connecting said resetting chamber with said discharge area so that said predetermined pressure in said pressure chamber moves said piston element to said operative position and said picking means to said picking position.
 11. Picking apparatus as claimed in claim 10 wherein said piston element is stepped so that the effective areas of said pressure chamber and said resetting chambers are different.
 12. Pneumatic picking apparatus for a loom, comprising, in combination, picking means movable between a position of rest and a picking position for driving a shuttle across the loom; pneumatic drive means including a cylinder element, and a piston element forming in said cylinder element a pressure chamber, one of said elements being movable and connected with said picking means for movement therewith; a pressure gas container and conduit means connecting said container with said pressure chamber so that said container, said conduit means, and said pressure chamber form a closed space filled with gas at a predetermined pressure for biassing said movable element to move from an initial position to an operative position for moving said picking means to said picking position whereby the pressure in said pressure chamber is partially relieved; resetting means for returning said movable element from said operative position to said initial position and for holding said movable element in said initial position whereby the initial predetermined pressure is again restored in said pressure chamber, and said picking means returned to said position of rest, said resetting means including resetting piston and cylinder means; and control means for operating said resetting means to release said movable element for movement to said operative position so that said movable element moves said picking means rapidly to said picking position, and to thereafter return said movable element to said initial position and said picking means to said position of rest, said control means including control valve means controlling said resetting piston and cylinder means to reset and release said pneumatic drive means, and operating means for said control valve means actuated by movable parts of the loom. 